c3bd503b43a2aa0ca50ce3ec23d405641c5fcd69
[linux-2.6.git] / arch / arm / mm / mm-armv.c
1 /*
2  *  linux/arch/arm/mm/mm-armv.c
3  *
4  *  Copyright (C) 1998-2002 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  *  Page table sludge for ARM v3 and v4 processor architectures.
11  */
12 #include <linux/config.h>
13 #include <linux/module.h>
14 #include <linux/mm.h>
15 #include <linux/init.h>
16 #include <linux/bootmem.h>
17 #include <linux/highmem.h>
18 #include <linux/nodemask.h>
19
20 #include <asm/pgalloc.h>
21 #include <asm/page.h>
22 #include <asm/io.h>
23 #include <asm/setup.h>
24 #include <asm/tlbflush.h>
25
26 #include <asm/mach/map.h>
27
28 #define CPOLICY_UNCACHED        0
29 #define CPOLICY_BUFFERED        1
30 #define CPOLICY_WRITETHROUGH    2
31 #define CPOLICY_WRITEBACK       3
32 #define CPOLICY_WRITEALLOC      4
33
34 static unsigned int cachepolicy __initdata = CPOLICY_WRITEBACK;
35 static unsigned int ecc_mask __initdata = 0;
36 pgprot_t pgprot_kernel;
37
38 EXPORT_SYMBOL(pgprot_kernel);
39
40 pmd_t *top_pmd;
41
42 struct cachepolicy {
43         const char      policy[16];
44         unsigned int    cr_mask;
45         unsigned int    pmd;
46         unsigned int    pte;
47 };
48
49 static struct cachepolicy cache_policies[] __initdata = {
50         {
51                 .policy         = "uncached",
52                 .cr_mask        = CR_W|CR_C,
53                 .pmd            = PMD_SECT_UNCACHED,
54                 .pte            = 0,
55         }, {
56                 .policy         = "buffered",
57                 .cr_mask        = CR_C,
58                 .pmd            = PMD_SECT_BUFFERED,
59                 .pte            = PTE_BUFFERABLE,
60         }, {
61                 .policy         = "writethrough",
62                 .cr_mask        = 0,
63                 .pmd            = PMD_SECT_WT,
64                 .pte            = PTE_CACHEABLE,
65         }, {
66                 .policy         = "writeback",
67                 .cr_mask        = 0,
68                 .pmd            = PMD_SECT_WB,
69                 .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
70         }, {
71                 .policy         = "writealloc",
72                 .cr_mask        = 0,
73                 .pmd            = PMD_SECT_WBWA,
74                 .pte            = PTE_BUFFERABLE|PTE_CACHEABLE,
75         }
76 };
77
78 /*
79  * These are useful for identifing cache coherency
80  * problems by allowing the cache or the cache and
81  * writebuffer to be turned off.  (Note: the write
82  * buffer should not be on and the cache off).
83  */
84 static void __init early_cachepolicy(char **p)
85 {
86         int i;
87
88         for (i = 0; i < ARRAY_SIZE(cache_policies); i++) {
89                 int len = strlen(cache_policies[i].policy);
90
91                 if (memcmp(*p, cache_policies[i].policy, len) == 0) {
92                         cachepolicy = i;
93                         cr_alignment &= ~cache_policies[i].cr_mask;
94                         cr_no_alignment &= ~cache_policies[i].cr_mask;
95                         *p += len;
96                         break;
97                 }
98         }
99         if (i == ARRAY_SIZE(cache_policies))
100                 printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
101         flush_cache_all();
102         set_cr(cr_alignment);
103 }
104
105 static void __init early_nocache(char **__unused)
106 {
107         char *p = "buffered";
108         printk(KERN_WARNING "nocache is deprecated; use cachepolicy=%s\n", p);
109         early_cachepolicy(&p);
110 }
111
112 static void __init early_nowrite(char **__unused)
113 {
114         char *p = "uncached";
115         printk(KERN_WARNING "nowb is deprecated; use cachepolicy=%s\n", p);
116         early_cachepolicy(&p);
117 }
118
119 static void __init early_ecc(char **p)
120 {
121         if (memcmp(*p, "on", 2) == 0) {
122                 ecc_mask = PMD_PROTECTION;
123                 *p += 2;
124         } else if (memcmp(*p, "off", 3) == 0) {
125                 ecc_mask = 0;
126                 *p += 3;
127         }
128 }
129
130 __early_param("nocache", early_nocache);
131 __early_param("nowb", early_nowrite);
132 __early_param("cachepolicy=", early_cachepolicy);
133 __early_param("ecc=", early_ecc);
134
135 static int __init noalign_setup(char *__unused)
136 {
137         cr_alignment &= ~CR_A;
138         cr_no_alignment &= ~CR_A;
139         set_cr(cr_alignment);
140         return 1;
141 }
142
143 __setup("noalign", noalign_setup);
144
145 #define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
146
147 static inline pmd_t *pmd_off(pgd_t *pgd, unsigned long virt)
148 {
149         return pmd_offset(pgd, virt);
150 }
151
152 static inline pmd_t *pmd_off_k(unsigned long virt)
153 {
154         return pmd_off(pgd_offset_k(virt), virt);
155 }
156
157 /*
158  * need to get a 16k page for level 1
159  */
160 pgd_t *get_pgd_slow(struct mm_struct *mm)
161 {
162         pgd_t *new_pgd, *init_pgd;
163         pmd_t *new_pmd, *init_pmd;
164         pte_t *new_pte, *init_pte;
165
166         new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
167         if (!new_pgd)
168                 goto no_pgd;
169
170         memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
171
172         /*
173          * Copy over the kernel and IO PGD entries
174          */
175         init_pgd = pgd_offset_k(0);
176         memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
177                        (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
178
179         clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
180
181         if (!vectors_high()) {
182                 /*
183                  * This lock is here just to satisfy pmd_alloc and pte_lock
184                  */
185                 spin_lock(&mm->page_table_lock);
186
187                 /*
188                  * On ARM, first page must always be allocated since it
189                  * contains the machine vectors.
190                  */
191                 new_pmd = pmd_alloc(mm, new_pgd, 0);
192                 if (!new_pmd)
193                         goto no_pmd;
194
195                 new_pte = pte_alloc_map(mm, new_pmd, 0);
196                 if (!new_pte)
197                         goto no_pte;
198
199                 init_pmd = pmd_offset(init_pgd, 0);
200                 init_pte = pte_offset_map_nested(init_pmd, 0);
201                 set_pte(new_pte, *init_pte);
202                 pte_unmap_nested(init_pte);
203                 pte_unmap(new_pte);
204
205                 spin_unlock(&mm->page_table_lock);
206         }
207
208         return new_pgd;
209
210 no_pte:
211         spin_unlock(&mm->page_table_lock);
212         pmd_free(new_pmd);
213         free_pages((unsigned long)new_pgd, 2);
214         return NULL;
215
216 no_pmd:
217         spin_unlock(&mm->page_table_lock);
218         free_pages((unsigned long)new_pgd, 2);
219         return NULL;
220
221 no_pgd:
222         return NULL;
223 }
224
225 void free_pgd_slow(pgd_t *pgd)
226 {
227         pmd_t *pmd;
228         struct page *pte;
229
230         if (!pgd)
231                 return;
232
233         /* pgd is always present and good */
234         pmd = pmd_off(pgd, 0);
235         if (pmd_none(*pmd))
236                 goto free;
237         if (pmd_bad(*pmd)) {
238                 pmd_ERROR(*pmd);
239                 pmd_clear(pmd);
240                 goto free;
241         }
242
243         pte = pmd_page(*pmd);
244         pmd_clear(pmd);
245         dec_page_state(nr_page_table_pages);
246         pte_free(pte);
247         pmd_free(pmd);
248 free:
249         free_pages((unsigned long) pgd, 2);
250 }
251
252 /*
253  * Create a SECTION PGD between VIRT and PHYS in domain
254  * DOMAIN with protection PROT.  This operates on half-
255  * pgdir entry increments.
256  */
257 static inline void
258 alloc_init_section(unsigned long virt, unsigned long phys, int prot)
259 {
260         pmd_t *pmdp = pmd_off_k(virt);
261
262         if (virt & (1 << 20))
263                 pmdp++;
264
265         *pmdp = __pmd(phys | prot);
266         flush_pmd_entry(pmdp);
267 }
268
269 /*
270  * Create a SUPER SECTION PGD between VIRT and PHYS with protection PROT
271  */
272 static inline void
273 alloc_init_supersection(unsigned long virt, unsigned long phys, int prot)
274 {
275         int i;
276
277         for (i = 0; i < 16; i += 1) {
278                 alloc_init_section(virt, phys & SUPERSECTION_MASK,
279                                    prot | PMD_SECT_SUPER);
280
281                 virt += (PGDIR_SIZE / 2);
282                 phys += (PGDIR_SIZE / 2);
283         }
284 }
285
286 /*
287  * Add a PAGE mapping between VIRT and PHYS in domain
288  * DOMAIN with protection PROT.  Note that due to the
289  * way we map the PTEs, we must allocate two PTE_SIZE'd
290  * blocks - one for the Linux pte table, and one for
291  * the hardware pte table.
292  */
293 static inline void
294 alloc_init_page(unsigned long virt, unsigned long phys, unsigned int prot_l1, pgprot_t prot)
295 {
296         pmd_t *pmdp = pmd_off_k(virt);
297         pte_t *ptep;
298
299         if (pmd_none(*pmdp)) {
300                 unsigned long pmdval;
301                 ptep = alloc_bootmem_low_pages(2 * PTRS_PER_PTE *
302                                                sizeof(pte_t));
303
304                 pmdval = __pa(ptep) | prot_l1;
305                 pmdp[0] = __pmd(pmdval);
306                 pmdp[1] = __pmd(pmdval + 256 * sizeof(pte_t));
307                 flush_pmd_entry(pmdp);
308         }
309         ptep = pte_offset_kernel(pmdp, virt);
310
311         set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
312 }
313
314 /*
315  * Clear any PGD mapping.  On a two-level page table system,
316  * the clearance is done by the middle-level functions (pmd)
317  * rather than the top-level (pgd) functions.
318  */
319 static inline void clear_mapping(unsigned long virt)
320 {
321         pmd_clear(pmd_off_k(virt));
322 }
323
324 struct mem_types {
325         unsigned int    prot_pte;
326         unsigned int    prot_l1;
327         unsigned int    prot_sect;
328         unsigned int    domain;
329 };
330
331 static struct mem_types mem_types[] __initdata = {
332         [MT_DEVICE] = {
333                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
334                                 L_PTE_WRITE,
335                 .prot_l1   = PMD_TYPE_TABLE,
336                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
337                                 PMD_SECT_AP_WRITE,
338                 .domain    = DOMAIN_IO,
339         },
340         [MT_CACHECLEAN] = {
341                 .prot_sect = PMD_TYPE_SECT,
342                 .domain    = DOMAIN_KERNEL,
343         },
344         [MT_MINICLEAN] = {
345                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_MINICACHE,
346                 .domain    = DOMAIN_KERNEL,
347         },
348         [MT_LOW_VECTORS] = {
349                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
350                                 L_PTE_EXEC,
351                 .prot_l1   = PMD_TYPE_TABLE,
352                 .domain    = DOMAIN_USER,
353         },
354         [MT_HIGH_VECTORS] = {
355                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
356                                 L_PTE_USER | L_PTE_EXEC,
357                 .prot_l1   = PMD_TYPE_TABLE,
358                 .domain    = DOMAIN_USER,
359         },
360         [MT_MEMORY] = {
361                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_AP_WRITE,
362                 .domain    = DOMAIN_KERNEL,
363         },
364         [MT_ROM] = {
365                 .prot_sect = PMD_TYPE_SECT,
366                 .domain    = DOMAIN_KERNEL,
367         },
368         [MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
369                 .prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
370                                 L_PTE_WRITE,
371                 .prot_l1   = PMD_TYPE_TABLE,
372                 .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
373                                 PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
374                                 PMD_SECT_TEX(1),
375                 .domain    = DOMAIN_IO,
376         }
377 };
378
379 /*
380  * Adjust the PMD section entries according to the CPU in use.
381  */
382 static void __init build_mem_type_table(void)
383 {
384         struct cachepolicy *cp;
385         unsigned int cr = get_cr();
386         int cpu_arch = cpu_architecture();
387         int i;
388
389 #if defined(CONFIG_CPU_DCACHE_DISABLE)
390         if (cachepolicy > CPOLICY_BUFFERED)
391                 cachepolicy = CPOLICY_BUFFERED;
392 #elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
393         if (cachepolicy > CPOLICY_WRITETHROUGH)
394                 cachepolicy = CPOLICY_WRITETHROUGH;
395 #endif
396         if (cpu_arch < CPU_ARCH_ARMv5) {
397                 if (cachepolicy >= CPOLICY_WRITEALLOC)
398                         cachepolicy = CPOLICY_WRITEBACK;
399                 ecc_mask = 0;
400         }
401
402         if (cpu_arch <= CPU_ARCH_ARMv5) {
403                 for (i = 0; i < ARRAY_SIZE(mem_types); i++) {
404                         if (mem_types[i].prot_l1)
405                                 mem_types[i].prot_l1 |= PMD_BIT4;
406                         if (mem_types[i].prot_sect)
407                                 mem_types[i].prot_sect |= PMD_BIT4;
408                 }
409         }
410
411         /*
412          * ARMv6 and above have extended page tables.
413          */
414         if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
415                 /*
416                  * bit 4 becomes XN which we must clear for the
417                  * kernel memory mapping.
418                  */
419                 mem_types[MT_MEMORY].prot_sect &= ~PMD_BIT4;
420                 mem_types[MT_ROM].prot_sect &= ~PMD_BIT4;
421                 /*
422                  * Mark cache clean areas and XIP ROM read only
423                  * from SVC mode and no access from userspace.
424                  */
425                 mem_types[MT_ROM].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
426                 mem_types[MT_MINICLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
427                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_APX|PMD_SECT_AP_WRITE;
428         }
429
430         cp = &cache_policies[cachepolicy];
431
432         if (cpu_arch >= CPU_ARCH_ARMv5) {
433                 mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
434                 mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte & PTE_CACHEABLE;
435         } else {
436                 mem_types[MT_LOW_VECTORS].prot_pte |= cp->pte;
437                 mem_types[MT_HIGH_VECTORS].prot_pte |= cp->pte;
438                 mem_types[MT_MINICLEAN].prot_sect &= ~PMD_SECT_TEX(1);
439         }
440
441         mem_types[MT_LOW_VECTORS].prot_l1 |= ecc_mask;
442         mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
443         mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
444         mem_types[MT_ROM].prot_sect |= cp->pmd;
445
446         for (i = 0; i < 16; i++) {
447                 unsigned long v = pgprot_val(protection_map[i]);
448                 v &= (~(PTE_BUFFERABLE|PTE_CACHEABLE)) | cp->pte;
449                 protection_map[i] = __pgprot(v);
450         }
451
452         pgprot_kernel = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG |
453                                  L_PTE_DIRTY | L_PTE_WRITE |
454                                  L_PTE_EXEC | cp->pte);
455
456         switch (cp->pmd) {
457         case PMD_SECT_WT:
458                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WT;
459                 break;
460         case PMD_SECT_WB:
461         case PMD_SECT_WBWA:
462                 mem_types[MT_CACHECLEAN].prot_sect |= PMD_SECT_WB;
463                 break;
464         }
465         printk("Memory policy: ECC %sabled, Data cache %s\n",
466                 ecc_mask ? "en" : "dis", cp->policy);
467 }
468
469 #define vectors_base()  (vectors_high() ? 0xffff0000 : 0)
470
471 /*
472  * Create the page directory entries and any necessary
473  * page tables for the mapping specified by `md'.  We
474  * are able to cope here with varying sizes and address
475  * offsets, and we take full advantage of sections and
476  * supersections.
477  */
478 static void __init create_mapping(struct map_desc *md)
479 {
480         unsigned long virt, length;
481         int prot_sect, prot_l1, domain;
482         pgprot_t prot_pte;
483         long off;
484
485         if (md->virtual != vectors_base() && md->virtual < TASK_SIZE) {
486                 printk(KERN_WARNING "BUG: not creating mapping for "
487                        "0x%08lx at 0x%08lx in user region\n",
488                        md->physical, md->virtual);
489                 return;
490         }
491
492         if ((md->type == MT_DEVICE || md->type == MT_ROM) &&
493             md->virtual >= PAGE_OFFSET && md->virtual < VMALLOC_END) {
494                 printk(KERN_WARNING "BUG: mapping for 0x%08lx at 0x%08lx "
495                        "overlaps vmalloc space\n",
496                        md->physical, md->virtual);
497         }
498
499         domain    = mem_types[md->type].domain;
500         prot_pte  = __pgprot(mem_types[md->type].prot_pte);
501         prot_l1   = mem_types[md->type].prot_l1 | PMD_DOMAIN(domain);
502         prot_sect = mem_types[md->type].prot_sect | PMD_DOMAIN(domain);
503
504         virt   = md->virtual;
505         off    = md->physical - virt;
506         length = md->length;
507
508         if (mem_types[md->type].prot_l1 == 0 &&
509             (virt & 0xfffff || (virt + off) & 0xfffff || (virt + length) & 0xfffff)) {
510                 printk(KERN_WARNING "BUG: map for 0x%08lx at 0x%08lx can not "
511                        "be mapped using pages, ignoring.\n",
512                        md->physical, md->virtual);
513                 return;
514         }
515
516         while ((virt & 0xfffff || (virt + off) & 0xfffff) && length >= PAGE_SIZE) {
517                 alloc_init_page(virt, virt + off, prot_l1, prot_pte);
518
519                 virt   += PAGE_SIZE;
520                 length -= PAGE_SIZE;
521         }
522
523         /* N.B. ARMv6 supersections are only defined to work with domain 0.
524          *      Since domain assignments can in fact be arbitrary, the
525          *      'domain == 0' check below is required to insure that ARMv6
526          *      supersections are only allocated for domain 0 regardless
527          *      of the actual domain assignments in use.
528          */
529         if (cpu_architecture() >= CPU_ARCH_ARMv6 && domain == 0) {
530                 /* Align to supersection boundary */
531                 while ((virt & ~SUPERSECTION_MASK || (virt + off) &
532                         ~SUPERSECTION_MASK) && length >= (PGDIR_SIZE / 2)) {
533                         alloc_init_section(virt, virt + off, prot_sect);
534
535                         virt   += (PGDIR_SIZE / 2);
536                         length -= (PGDIR_SIZE / 2);
537                 }
538
539                 while (length >= SUPERSECTION_SIZE) {
540                         alloc_init_supersection(virt, virt + off, prot_sect);
541
542                         virt   += SUPERSECTION_SIZE;
543                         length -= SUPERSECTION_SIZE;
544                 }
545         }
546
547         /*
548          * A section mapping covers half a "pgdir" entry.
549          */
550         while (length >= (PGDIR_SIZE / 2)) {
551                 alloc_init_section(virt, virt + off, prot_sect);
552
553                 virt   += (PGDIR_SIZE / 2);
554                 length -= (PGDIR_SIZE / 2);
555         }
556
557         while (length >= PAGE_SIZE) {
558                 alloc_init_page(virt, virt + off, prot_l1, prot_pte);
559
560                 virt   += PAGE_SIZE;
561                 length -= PAGE_SIZE;
562         }
563 }
564
565 /*
566  * In order to soft-boot, we need to insert a 1:1 mapping in place of
567  * the user-mode pages.  This will then ensure that we have predictable
568  * results when turning the mmu off
569  */
570 void setup_mm_for_reboot(char mode)
571 {
572         unsigned long pmdval;
573         pgd_t *pgd;
574         pmd_t *pmd;
575         int i;
576         int cpu_arch = cpu_architecture();
577
578         if (current->mm && current->mm->pgd)
579                 pgd = current->mm->pgd;
580         else
581                 pgd = init_mm.pgd;
582
583         for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++) {
584                 pmdval = (i << PGDIR_SHIFT) |
585                          PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
586                          PMD_TYPE_SECT;
587                 if (cpu_arch <= CPU_ARCH_ARMv5)
588                         pmdval |= PMD_BIT4;
589                 pmd = pmd_off(pgd, i << PGDIR_SHIFT);
590                 pmd[0] = __pmd(pmdval);
591                 pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));
592                 flush_pmd_entry(pmd);
593         }
594 }
595
596 extern void _stext, _etext;
597
598 /*
599  * Setup initial mappings.  We use the page we allocated for zero page to hold
600  * the mappings, which will get overwritten by the vectors in traps_init().
601  * The mappings must be in virtual address order.
602  */
603 void __init memtable_init(struct meminfo *mi)
604 {
605         struct map_desc *init_maps, *p, *q;
606         unsigned long address = 0;
607         int i;
608
609         build_mem_type_table();
610
611         init_maps = p = alloc_bootmem_low_pages(PAGE_SIZE);
612
613 #ifdef CONFIG_XIP_KERNEL
614         p->physical   = CONFIG_XIP_PHYS_ADDR & PMD_MASK;
615         p->virtual    = (unsigned long)&_stext & PMD_MASK;
616         p->length     = ((unsigned long)&_etext - p->virtual + ~PMD_MASK) & PMD_MASK;
617         p->type       = MT_ROM;
618         p ++;
619 #endif
620
621         for (i = 0; i < mi->nr_banks; i++) {
622                 if (mi->bank[i].size == 0)
623                         continue;
624
625                 p->physical   = mi->bank[i].start;
626                 p->virtual    = __phys_to_virt(p->physical);
627                 p->length     = mi->bank[i].size;
628                 p->type       = MT_MEMORY;
629                 p ++;
630         }
631
632 #ifdef FLUSH_BASE
633         p->physical   = FLUSH_BASE_PHYS;
634         p->virtual    = FLUSH_BASE;
635         p->length     = PGDIR_SIZE;
636         p->type       = MT_CACHECLEAN;
637         p ++;
638 #endif
639
640 #ifdef FLUSH_BASE_MINICACHE
641         p->physical   = FLUSH_BASE_PHYS + PGDIR_SIZE;
642         p->virtual    = FLUSH_BASE_MINICACHE;
643         p->length     = PGDIR_SIZE;
644         p->type       = MT_MINICLEAN;
645         p ++;
646 #endif
647
648         /*
649          * Go through the initial mappings, but clear out any
650          * pgdir entries that are not in the description.
651          */
652         q = init_maps;
653         do {
654                 if (address < q->virtual || q == p) {
655                         clear_mapping(address);
656                         address += PGDIR_SIZE;
657                 } else {
658                         create_mapping(q);
659
660                         address = q->virtual + q->length;
661                         address = (address + PGDIR_SIZE - 1) & PGDIR_MASK;
662
663                         q ++;
664                 }
665         } while (address != 0);
666
667         /*
668          * Create a mapping for the machine vectors at the high-vectors
669          * location (0xffff0000).  If we aren't using high-vectors, also
670          * create a mapping at the low-vectors virtual address.
671          */
672         init_maps->physical   = virt_to_phys(init_maps);
673         init_maps->virtual    = 0xffff0000;
674         init_maps->length     = PAGE_SIZE;
675         init_maps->type       = MT_HIGH_VECTORS;
676         create_mapping(init_maps);
677
678         if (!vectors_high()) {
679                 init_maps->virtual = 0;
680                 init_maps->type = MT_LOW_VECTORS;
681                 create_mapping(init_maps);
682         }
683
684         flush_cache_all();
685         local_flush_tlb_all();
686
687         top_pmd = pmd_off_k(0xffff0000);
688 }
689
690 /*
691  * Create the architecture specific mappings
692  */
693 void __init iotable_init(struct map_desc *io_desc, int nr)
694 {
695         int i;
696
697         for (i = 0; i < nr; i++)
698                 create_mapping(io_desc + i);
699 }